Joule Heat Encapsulating Apparatus and Encapsulating Method Using the Same

ABSTRACT

In a Joule heat encapsulating apparatus and an encapsulating method using the same, a panel is mounted on a stage, the panel including a thermal-hardening type sealant for surrounding and sealing a display unit formed between a first substrate and a second substrate, a heat-generating wiring overlapping the thermal-hardening type sealant, and an electric current application wiring connected to the heat-generating wiring. A cap is employed to form a sealed space, in which the panel is arranged, between the stage and the cap. An exhaustion mechanism for exhausting air in the sealed space, and a power applying mechanism connected to the electric current application wiring for supplying a current to the heat-generating wiring, are provided. As a result, a stable encapsulating structure which prevents permeation of oxygen or moisture may be easily formed.

CLAIM OF PRIORITY

This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application earlier filed in the Korean Intellectual Property Office on Aug. 18, 2010 and there duly assigned Serial No. 10-2010-0079851.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an encapsulating apparatus for encapsulating a display unit of a flat panel display device, and more particularly, to an encapsulating apparatus for performing encapsulation by using Joule heat.

2. Description of the Related Art

Flat panel display devices, e.g., an organic light-emitting display device, may be fabricated so as to be thin and flexible due to operating properties, and thus a variety of research is being conducted thereon.

However, such flat panel display devices have a property such that a display unit thereof is deteriorated by permeation of oxygen or moisture. Therefore, th flat panel display devices require an encapsulating structure for encapsulating and protecting a display unit by preventing permeation of oxygen or moisture. To form the encapsulating structure, an encapsulating apparatus is required for convenient formation of a stable encapsulating structure which prevents permeation of oxygen or moisture.

SUMMARY OF THE INVENTION

The present invention provides an encapsulating apparatus for convenient formation of a stable encapsulating structure which prevents permeation of oxygen or moisture, and an encapsulating method using the encapsulating apparatus.

According to an aspect of the present invention, a Joule heat encapsulating apparatus comprises: a stage to which a panel is mounted, the panel including a thermal-hardening type sealant for surrounding and sealing a display unit formed between a first substrate and a second substrate, a heat-generating wiring overlapping the thermal-hardening type sealant, and an electric current application wiring connected to the heat-generating wiring; a cap for forming a sealed space, in which the panel is arranged, between the stage and the cap; an exhaustion mechanism for exhausting air in the sealed space; and a power applying mechanism which is connected to the electric current application wiring, and which supplies a current to the heat-generating wiring.

The Joule heat encapsulating apparatus may further include a sealing member which is elastically pressed between the stage and the cap, and which maintains the sealed space airtight.

The sealing member may include a silicon O-ring or a cellular rubber O-ring.

The thermal-hardening type sealant may include frit.

The exhaustion mechanism may include an exhaustion hose connected to a via hole formed in the cap and a vacuum pump for sucking out the air via the exhaustion hose.

The power applying mechanism may include an electrode member which is attached to the cap so as to contact the electric current application wiring, and a power source connected to the electrode member.

A plurality of the electric current application wirings may be formed, and a plurality of electrode members may be formed in correspondence to the plurality of electric current application wirings.

A pressing unit for pressing the panel when the cap is adhered to the stage may be formed on the cap.

According to another aspect of the present invention, a Joule heat encapsulating method comprises: mounting a panel on a stage, the panel including a thermal-hardening type sealant for surrounding and sealing a display unit formed between a first substrate and a second substrate, a heat-generating wiring overlapping the thermal-hardening type sealant, and an electric current application wiring connected to the heat-generating wiring; forming a sealed space, in which the panel is arranged, between the stage and a cap by covering the stage with the cap; exhausting air in the sealed space; and hardening the thermal-hardening type sealant by supplying a current to the heat-generating wiring via the electric current application wiring.

The Joule heat encapsulating method may further include maintaining the sealed space airtight by interposing a sealing member which is elastically pressed between the stage and the cap.

The sealing member may include a silicon O-ring or a cellular rubber O-ring.

The Joule heat encapsulating method may further include pressing the panel when the cap is adhered to the stage by using a pressing unit formed on the cap.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which like reference symbols indicate the same or similar components, wherein:

FIG. 1 is an exploded perspective view of a Joule heat encapsulating apparatus according to an embodiment of the present invention;

FIG. 2 is plan view of the Joule heat encapsulating apparatus of FIG. 1;

FIG. 3 is a sectional view taken along a line A-A of FIG. 2;

FIG. 4 is a plan view showing the structure of a display unit of the panel shown in FIG. 1; and

FIG. 5 is a plan view showing a modified example of the panel shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present invention will be described in detail by explaining embodiments of the invention with reference to the attached drawings.

First, a Joule heat encapsulating apparatus according to the present invention is an apparatus for performing an encapsulating operation by using Joule heat generated when a current flows in a conductor, and it may have a structure as shown in FIGS. 1 thru 3, for example.

FIG. 1 is an exploded perspective view of a Joule heat encapsulating apparatus according to an embodiment of the present invention; FIG. 2 is plan view of the Joule heat encapsulating apparatus of FIG. 1; and FIG. 3 is a sectional view taken along a line A-A of FIG. 2.

Referring to FIGS. 1 thru 3, the Joule heat encapsulating apparatus according to the present embodiment includes a stage 10 to which a panel 100 is mounted, and a cap 20 which covers the stage 10 so as to seal around the panel 100. In other words, a sealed space S (refer to FIG. 3) housing the panel 100 is formed by mounting the panel 100 on the stage 10 and covering the stage 10 with the cap 20.

In FIG. 2, since a cap 20 and a second substrate 102 are formed of transparent materials, components therebelow may be seen therethrough.

Next, a sealing member 30 is adhered to the cap 20. The sealing member 30 firmly maintains the sealed space S airtight by elastically compressing when the cap 20 covers the stage 10.

The stage 10 and the cap 20 may be formed of an acrylic material. Furthermore, the sealing member 30 may be formed of a silicon O-ring or a cellular rubber O-ring. Here, since a cellular rubber O-ring has higher elasticity than a silicon O-ring, a cellular rubber O-ring may be used for smooth adherence between the cap 20 and the stage 10. If a silicon O-ring with relatively low elasticity is used, the sealing member 30 may not absorb sufficient pressure when the cap 20 is adhered to the stage 10, and thus the stage 10 may be bent.

An electrode member 41, which is connected to a power source 42, is attached to the cap 20 as a power applying mechanism 40 for supplying a current to the panel 100 so as to generate Joule heat. The electrode member 41 contacts an electric current application wiring 160 of the panel 100 when the cap 20 is attached to the stage 10 with the sealing member 30.

Furthermore, an exhaustion hose 51 and a vacuum pump 52, which are connected to a via hole 22 formed in the cap 20, are formed as an exhaustion mechanism 50 for exhausting air in the sealed space S. Therefore, when the vacuum pump 52 operates, the air in the sealed space S is exhausted via the exhaustion hose 51, and thus the sealed space S becomes nearly vacuum.

Detailed descriptions on operations of the Joule heat encapsulating apparatus will be given below. Here, the structure of the panel 100, on which an encapsulating operation is performed, will be described.

The panel 100 is a component constituting a flat panel display device, such as an organic light-emitting display device, and includes a first substrate 101 and a second substrates 102 facing the first substrate 101, a display unit 110 which is formed between the first substrate 101 and second substrate 102, a thermal-hardening type sealant 170 which surrounds and seals the display unit 110, a heat-generating wiring 150 which is arranged so as to overlap the thermal-hardening type sealant 170, and the electric current application wiring 160. Therefore, when a current flows in the heat-generating wiring 150 via the electric current application wiring 160, Joule heat is generated and the thermal-hardening type sealant 170 is hardened. As a result, a space between the first and second substrates 101 and 102 is firmly sealed by the sealant 170, and thus the display unit 110 is protected.

The first substrate 101 may be formed of an SiO₂-based transparent glass material. However, the present invention is not limited thereto, and the first substrate 101 may also be formed of a transparent plastic material. In the latter case, the transparent plastic material for forming the first substrate 101 may be an organic insulation material selected from a group consisting of polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethyelene naphthalate (PEN), polyethyelene terephthalate (PET), polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), and cellulose acetate propionate (CAP).

Furthermore, the display unit 110 is arranged on the first substrate 101 as described above. The display unit 110 may be any of various types. Although the display unit 110 includes an organic light-emitting display device in the present embodiment, the present invention is not limited thereto, and the display unit 110 may include a liquid crystal display device.

The second substrate 102, which is a sealing substrate, is arranged on the display unit 110, and the thermal-hardening type sealant 170 is arranged between the first and second substrates 101 and 102, respectively. The thermal-hardening type sealant 170 maybe formed so as to surround the display unit 110. The thermal-hardening type sealant 170 may include frit.

Next, the heat-generating wiring 150 is formed so as to overlap the thermal-hardening type sealant 170. In other words, the heat-generating wiring 150 is formed on the first substrate 101, and the thermal-hardening type sealant 170 is formed on the heat-generating wiring 150 so as to overlap the heat-generating wiring 150.

The heat-generating wiring 150 may be formed of any of various conductive materials.

The electric current application wiring 160 connected to the heat-generating wiring 150 is arranged on the first substrate 101, and the electric current application wiring 160 may be formed of the same material as the heat-generating wiring 150.

Here, the width W1 (FIG. 1) of the electric current application wiring 160 may be greater than the width W2 of the heat-generating wiring 150. As described above, a current flows to the heat-generating wiring 150 via the electric current application wiring 160. Since a current flowing in the electric current application wiring 160 flows in a divided manner to the left side and the right side of the heat-generating wiring 150, more load may be generated in the electric current application wiring 160 than in the heat-generating wiring 150. For example, in the case where the width W1 of the electric current application wiring 160 is the same as the width W2 of the heat-generating wiring 150, heat generated in the electric current application wiring 160 may be twice as much as heat generated in the heat-generating wiring 150, and thus the electric current application wiring 160 may be damaged. Therefore, the width W1 of the electric current application wiring 160 may be at least twice as much as the width W2 of the heat-generating wiring 150 so as to prevent the electric current application wiring 160 from overheating.

In the present embodiment, each of two electric current application wirings 160 is formed at both ends of the heat-generating wiring 150 (see FIG. 2). However, more than two electric current application wirings 160 may be arranged if necessary. When a current flows to the heat-generating wiring 150 via the electric current application wirings 160 and Joule heat is generated, the thermal-hardening type sealant 170 is hardened by the Joule heat.

The display unit 110 may be any of various types as stated above, and the present embodiment discloses the display unit 110 employing an organic light-emitting device. Detailed description of the display unit 110 will be given below with reference to FIG. 4.

FIG. 4 is a plan view showing the structure of a display unit of the panel shown in FIG. 1.

First, a buffer layer 111 is formed on the first substrate 101. The buffer layer 111 provides a flat surface on the first substrate 101 and prevents permeation of moisture and impurities into the first substrate 101.

An active layer 112 having a predetermined pattern is formed on the buffer layer 111. The active layer 112 may be formed of an inorganic semiconductor, e.g., amorphous silicon or poly-silicon, or an organic semiconductor, and includes a source region, a drain region, and a channel region.

The source region and the drain region may be formed by doping the active layer 112, which is formed of amorphous silicon or poly-silicon, with impurities. A p-type semiconductor may be formed by doping the active layer 112 with a Group III atom, e.g., boron (B), whereas an n-type semiconductor may be formed by doping the active layer 112 with a Group V atom, e.g., nitrogen (N).

A gate insulation layer 113 is formed on the active layer 112, and a gate electrode 114 is formed in a predetermined region on the gate insulation layer 113. The gate insulation layer 113 is a layer for insulating the active layer 112 from the gate electrode 114, and may be formed of an organic material or an inorganic material, e.g., SiNx or SiO₂.

The gate electrode 114 may be formed of a metal, such as Au, Ag, Cu, Ni, Pt, Pd, Al, or Mo, or a metal alloy, such as Al:Nd or Mo:W. However, the present invention is not limited thereto, and the gate electrode 114 may be formed of any of various materials in consideration of adherence, planarity, electric resistance, and manufacturability. The gate electrode 114 is connected to a gate line (not shown), by means of which an electric signal is applied.

An interlayer insulation layer 115 is formed on the gate electrode 114. The interlayer insulation layer 115 and the gate insulation layer 113 expose the source region and the drain region of the active layer 112, and a source electrode 116 and a drain electrode 117 are connected to the exposed source and drain regions, respectively, of the active layer 112.

The source electrode 116 and the drain electrode 117 may be formed of a metal, such as Au, Pd, Pt, Ni, Rh, Ru, Ir, or Os, or an alloy of two or more metals, such as Al:Mo, Al:Nd, or MoW. However, the present invention is not limited thereto.

Next, a passivation layer 118 is formed so as to cover the source electrode 116 and the drain electrode 117. The passivation layer 118 may be formed of an inorganic insulation layer and/or an organic insulation layer. The inorganic insulation layer may include SiO₂, SiN_(x), SiON, Al₂O₃, TiO₂, Ta₂O₅, HfO₂, ZrO₂, BST, or PZT, and the organic insulation layer may include a general-purpose polymer, such as poly (methyl methacrylate (PMMA) or polystyrene (PS), a polymer derivative containing a phenol group, an acrylic polymer, an imide-based polymer, an arylene-ether-based polymer, an amide-based polymer, a fluorine-based polymer, a p-xylene-based polymer, a vinyl-alcoholic polymer, or a blend thereof. The passivation layer 118 may also be formed as a composite stacked structure of an inorganic insulation layer and an organic insulation layer.

The passivation layer 118 exposes a portion of the drain electrode 117, and an organic light-emitting device 120 is formed so as to be connected to the exposed portion of the drain electrode 117. The organic light-emitting device 120 includes a first electrode 121, a second electrode 122, and an organic light-emitting layer 123. In detail, the first electrode 121 and the drain electrode 117 contact each other.

The organic light-emitting layer 123 emits visible rays when voltages are applied thereto via the first electrode 121 and the second electrode 122.

A pixel define layer (PDL) 119 is formed on the first electrode 121, the PDL 119 being formed of an insulation material. A predetermined opening is formed in the PDL 119 so as to expose a portion of the first electrode 121, and the organic light-emitting layer 123 is formed on the exposed portion of the first electrode 121. Next, the second electrode 122 is formed so as to be connected to the organic light-emitting layer 123.

The first electrode 121 and the second electrode 122 have polarities of an anode electrode and a cathode electrode, respectively. However, the polarities of the first electrode 121 and the second electrode 122 may be reversed.

Operations of encapsulating the panel 100 for sealing the display unit 110 from external air are performed as described below by using a Joule heat encapsulating apparatus according to the present embodiment.

First, the panel 100 is mounted on the stage 10.

The panel 100 has a structure in which the display unit 110 is formed between the first and second substrates 101 and 102, the heat-generating wiring 150 and the thermal-hardening type sealant 170, which overlap each other, surround the display unit 110, and the electric current application wiring 160 is connected to the heat-generating wiring 150. Furthermore, the electric current application wiring 160 extends outside the second substrate 102 so that the electrode member 41 may contact the electric current application wiring 160 from above.

At this point, the cap 20 is adhered to the stage 10 so as to house the panel 100 in the sealed space S between the cap 20 and the stage 10. Here, the electrode member 41 contacts and is electrically connected to the electric current application wiring 160, and the sealing member 30 is elastically pressed so as to firmly maintain the sealed space S between the cap 20 and the stage 10 airtight. Furthermore, a pressing unit 21, which is formed on the bottom surface of the cap 20, presses the panel 100 as shown in FIG. 3 so as to fix the panel 100 so that the panel 100 does not move.

Accordingly, when the cap 20 and the stage 10 are adhered to each other, the air in the sealed space S is exhausted to the outside via the exhaustion hose 51 by operating the vacuum pump 52. As a result, the sealed space S is nearly vacuum, and thus the panel 100 is located in a vacuum chamber.

Next, a current is supplied by the power source 42 via the electrode member 41, and a current flows to the heat-generating wiring 150 via the electric current application wiring 160, and Joule heat is generated in the heat-generating wiring 150.

As a result, the thermal-hardening type sealant 170, which overlaps the heat-generating wiring 150, is hardened and firmly seals the display unit 110 between the first and second substrates 101 and 102, respectively.

Therefore, a sturdy encapsulation structure may be formed by simple operations, including mounting the panel 100 on the stage 10, covering the panel 100 with the cap 20, and applying a current thereto.

FIG. 5 is a plan view showing a modified example of the panel shown in FIG. 1.

Although the present embodiment discloses the case in which one display unit 110 is formed in the panel 100, a plurality of display units 110 may be formed in a single panel 100 as shown in FIG. 5, and may be divided into individual units after encapsulation. Even in this case, since the heat-generating wirings 150 overlap with the thermal-hardening type sealant 170 of each of the display units 110, which are all connected to the electric current application wiring 160, the encapsulating operation, in which a current is supplied to the heat-generating wirings 150 via the electric current application wiring 160 so as to generate heat, may be performed as described above. Therefore, the present invention is not limited to the number of display units 110 included in the panel 100.

Furthermore, although the stage 10 and the cap 20 have rectangular shapes in the present embodiment, the stage 10 and the cap 20 may have circular shapes or any of a variety of polygonal shapes.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. 

What is claimed is:
 1. A Joule heat encapsulating apparatus, comprising: a stage on which a panel is mounted, the panel including a thermal-hardening type sealant for surrounding and sealing a display unit formed between a first substrate and a second substrate, a heat-generating wiring overlapping the thermal-hardening type sealant, and an electric current application wiring connected to the heat-generating wiring; a cap for forming a sealed space, in which the panel is arranged, between the stage and the cap; an exhaustion mechanism for exhausting air in the sealed space; and a power applying mechanism connected to the electric current application wiring and supplying current to the heat-generating wiring.
 2. The Joule heat encapsulating apparatus of claim 1, further comprising a sealing member which is elastically pressed between the stage and the cap, and which maintains the sealed space airtight.
 3. The Joule heat encapsulating apparatus of claim 2, wherein the sealing member comprises one of a silicon O-ring and a cellular rubber O-ring.
 4. The Joule heat encapsulating apparatus of claim 1, wherein the thermal-hardening type sealant comprises frit.
 5. The Joule heat encapsulating apparatus of claim 1, wherein the exhaustion mechanism comprises an exhaustion hose connected to a via hole formed in the cap, and a vacuum pump for sucking out the air via the exhaustion hose.
 6. The Joule heat encapsulating apparatus of claim 1, wherein the power applying mechanism comprises an electrode member attached to the cap so as to contact the electric current application wiring, and a power source connected to the electrode member.
 7. The Joule heat encapsulating apparatus of claim 6, wherein a plurality of the electric current application wirings are formed, and a plurality of electrode members are formed in correspondence to the plurality of electric current application wirings.
 8. The Joule heat encapsulating apparatus of claim 1, wherein a plurality of the electric current application wirings are formed, and a plurality of electrode members are formed in correspondence to the plurality of electric current application wirings.
 9. The Joule heat encapsulating apparatus of claim 1, further comprising a pressing unit formed on the cap for pressing the panel so that the cap is adhered to the stage.
 10. A Joule heat encapsulating method, comprising the steps of: mounting a panel on a stage, the panel including a thermal-hardening type sealant for surrounding and sealing a display unit formed between a first substrate and a second substrate, a heat-generating wiring overlapping the thermal-hardening type sealant, and an electric current application wiring connected to the heat-generating wiring; forming a sealed space, in which the panel is arranged, between the stage and a cap by covering the stage with the cap; exhausting air in the sealed space; and hardening the thermal-hardening type sealant by supplying a current to the heat-generating wiring via the electric current application wiring.
 11. The Joule heat encapsulating method of claim 10, further comprising maintaining the sealed space airtight by interposing a sealing member which is elastically pressed between the stage and the cap.
 12. The Joule heat encapsulating method of claim 11, wherein the sealing member comprises one of a silicon O-ring and a cellular rubber O-ring.
 13. The Joule heat encapsulating method of claim 10, further comprising the step of pressing the panel so that the cap is adhered to the stage by using a pressing unit formed on the cap. 